THE white birch of our northern woods seems to hold within its veins more of the elixir of ancient Pagandom than any other of our impulsive, untended wood-growths.

The white birch of Europe is the silver birch, Betula pendula, named for the way its branches hang down. You will find self-seeded thickets of it from Bavaria to Scotland and beyond.

Q: In the spring of 1986 we planted a European weeping white birch in the middle of our rose garden. It was looking great until about two months ago when it started looking paler and paler. All ...